The present invention relates in general to lifting devices, and more particularly, to devices for lifting heavy and bulky panels.
In the fabrication of concrete panels for use in modular buildings, and the like, the panels are often slip-formed on long line casting beds with the exterior panel surfaces textured in a variety of patterns. The panels are sawn to the required length, and finished panels are removed from the casting beds and stockpiled for later delivery and use. At the construction site, panels are hoisted into position by erecting crews using lifting devices.
There are several ways for handling such panels during the fabrication process, including a method utilizing ice tong-like gripping members, such as self-gripping claw grab or grip tongs, or the like. Such ice tong-like devices are suitable for use on panels having widths of 4 feet or less, but are not suitable for wider panels as the pressure applied to the panel by such gripping devices may crush or otherwise damage the panel. Sometimes lifting loops are embedded in the top surface of the panel for handling purposes (common for floor members), but this is unsightly and unacceptable for wall panels.
One device proposed for use with wide panels includes reinforcing hardware embedded in the panel itself. However, such a device produces a very slow operation and requires costly hardware.
The device embodying the teachings of the present invention has pivot points for the panel gripping elements located so that sufficient lifting pressure can be applied to the panel to lift large panels without crushing those panels.